Abstract

This report presents the results from theoretical considerations and practical tests concerning the influence of slip generated shear on the compaction of agricultural soil. The slip mechanics is reviewed and its influence on the stress field below a wheel or track is investigated. It is shown that shear stresses in the interface between wheel and soil have great influence on the magnitude of the major principal stress acting in the upper soil layer. Tests with shear displacement introduced by means of a torsional shearing device indicated increases in soil density due to shear at moderate normal stress. By means of field tests with a simple shear plate it was shown that the shear strain only affected the upper 2 cm of the soil below the shear plate.